Wednesday, June 27, 2012

More Frankenfood Paradox!

On Sunday there was considerable confusion about the alleged "GMO" grass that killed cattle. Turns out it was not GMO grass at all, but a hybrid. CBS has since retracted the story. In the meantime I received many inquiries about the difference between a GMO and a hybrid, as the latter sounded truly freaky and much more invasive than any frankenfood.

While hybrids are not the technology we usually think of with the terms genetic modification or genetic engineering, it is just that-- humans manipulating plants by modifying the genes of an organism toward crop improvement. No lab needed, just cross two sexually compatible plants that are different! The next generation has literally tens of thousands of new gene variants, and maybe new genes, that are different from the parents.

So let's scrap the pedestrian term GMOs and work with something more precise: transgenic. This means that the plants contain a gene inserted using recombinant DNA technology.

To clarify the issue on Sunday I slammed a table together that contrasted transgenic technology against other methods of plant improvement. A look at the table reveals that all are methods of genetic modification, and everything we eat is truly a genetically modified organism, especially when compared to wild, ancient antecedents.

Since then, I've enjoyed feedback from colleagues and readers, and did a little thinking and googling. Here is the new and improved table:

New and Improved! Take a look at the methods used to improve plants

by manipulating their genes. Some of these methods have been in place for 20,000 years.

Click on it for a larger version.

Particularly, please compare:
1. How many genes are transferred.
2. If we know where transferred or affected genes are located
3. If we know what transferred or affected genes do
4 If genes can be used from one species to another
5. If plant products are acceptable for organic cultivation
6. If laws are pending to label the products
7. How long it takes to make an improved plant product

Now honestly answer these questions:
1. Which technology is most precise?
2. Which technology is best understood?
3. Did you realize that humans have intervened to create so many common foods?
4. Did you know that you regularly consumed so many genetically altered products?
5. Isn't it amazing that humans just implement nature's own tools to improve plants?

I hope this helps your understanding. Thanks to everyone that offered such great feedback. Maybe together we can share an honest discussion to take the franken out of frankenfood, and use the best available safe and proven technologies to shape the future of food.

Kevin, I am not a molecular biologist, therefore I do not read that peer-reviewed literature regularly. Nevertheless, I have been struck by how many recent papers I have come across showing evidence of natural horizontal transmission of genetic material in evolutionary history. My collection of such papers is rapidly growing. This seems to directly challenge any notion that GMOs are "unnatural". In fact, I even posit that, because horizontal transfer occurs in natural ecosystems, genetic engineering is merely a mimic of nature and therefore is consistent with agroecological principles. I wonder what your thoughts are about this.

- "But the technique of genetic engineering is new, and quite different from conventional breeding. Traditional breeders cross related organisms whose genetic makeups are similar. In so doing, they transfer tens of thousands of genes. By contrast, today's genetic engineers can transfer just a few genes at a time between species that are distantly related or not related at all."

I never gave this post formal recognition for the substantial role it played in changing my opinions on biotechnology in agriculture. I'd like to correct that now and say Thank You, Kevin, for all you do.

Also for anyone finding this via Google or link I've left along the way, the Genetic Literacy Project has a very simplified version of this chart that may be useful in certain forums for the layperson. It took a long time for me, as a non-scientist, to fully appreciate Kevin's chart here and the GLP version might have moved me along just a little quicker. Both are invaluable in their own way.

Hybridization can occur within a species or across species. When it occurs across species, it may occur between species having very similar genes, or between species that are very far apart but we can somehow get lucky with them. The distinction is important because the first kind of hybridization has been the most pervasive one (as a result of it being most easy), and this kind of hybridization is just your usual sexual reproduction.

That is a first limitation of the table that can throw you off.

When each of my children was born, hundreds of thousands of genes in their genotypes were different from mine. That's true of all the species practicing sexual reproduction, be it humans, plants, what have you.

That's business as usual for nature. Why does it work? Because generally, all those hundreds of thousands of genes that change in the offspring each and every time come from the genotype of individuals that have been proven functional in nature. Most of those genes have already proven that they can express themselves *within the genotype of the species*, and they have done so for generations.

At the other pole, there is an intuition for those who hobby in genetics that placing a foreign gene in an organism generally causes deleterious changes (i.e., it reduces its fitness, may kill it or make it unable to reproduce). That intuition is correct. Why? Because the new gene can bind to the chemical products of the cellular processes and interfere with the program in ways that we can't understand.

Now, try to reconcile the facts mentioned in the above two paragraphs with what the table conveys when you compare GMOs and hybrids with regard to number of genes changed: the table squarely says that GMO is much, much safer than hybridization. So, does that fit with what you know about Nature's workings? Of course not.

That was another limitation of the table that can throw you off.

What of "human intervention"? The human intervention in the case of GMOs is highly invasive, with foreign viruses and foreign genes being inserted into the gene. With hybrids, it's limited to facilitating the crossing and making a value judgement to select an offspring.

That entire row tells no story about the nature of the intervention, let alone about its dangerousness.

What about the location of the gene in the genome? Only some GMO techniques target a specific DNA section, others are just trial and error.

I could go on. Behind some binarized (yes versus no) entries lie probabilities. "Occurs in nature" is an eloquent example. HGT occurs in nature in very low proportions, in the order of hundreds of years or more. In GMOs, we can expect, as per another row in the table, to have a new HGT every five years.

Horizontal gene transfer can cause deleterious or dangerous genetic changes, just as it can produce positive ones (as evidence by the natural instances we are discovering). For that reason, GMOs should be tested for safety, as they are.

Conventional crop improvement techniques (including tissue-culture and mutation breeding) can also result in deleterious or dangerous genetic changes, though crops derived from these techniques are rarely tested for safety under the unsupportable assumption that genetic changes produced by older techniques are benign. This is why numerous prestigious scientific organizations like the National Academy of Sciences have position papers that essentially say that, what matters is not how a genetic change was made, but what the genetic change does in the plant.

It is also true that natural HGT is tested through natural selection over millennia, but crop improvement is nothing more than human-driven, accelerated evolution. All crop improvement techniques identify low-frequency traits of interest and increase their frequency by artificial means. Even hybridization followed by repetitive backcrossing is not really a natural process. I don’t see a fundamentally different or dangerous process taking place with genetic engineering, and this interpretation seems consistent with those of numerous prestigious scientific societies.

I see natural HGT and other bizarre genetic manipulations (like mobile genetic elements) as simply a way that Nature generates biodiversity. It seems to me that we are simply mimicking these processes, though we are doing so with forethought and systematic evaluation.

Some ask, why take the risk? That is a fair question upon which reasonable people may disagree. I study the risks and always watch for new literature that highlights important aspects of the risks, but I also see great potential benefits, especially when made available in the public domain: greater food security for impoverished people; greatly improved nutrition for them as well; improved nutrition for wealthier populations; enhancement of pro-health nutrition factors; improved tolerance to environmental stresses related to global warming; improved crop nutrition with less use of fertilizer; reduced pesticide use; etc. I think we are making a big mistake to shut the door on this technology, instead of evaluating its use on a case-by-case basis.

First of all, we should clarify terminology here, to be sure we are talking about the same concepts:* Traditional breeding: little to no pesticides, hybridization techniques.* Conventional breeding: chemical or radiation-based manipulation of DNAs.* Genetic engineering: insertion of genes, generally foreign to the genome, using various vectors, currently viral or bacterial.

We must not fall victim to binarizing the properties of the technologies we seek to compare. We can't defend Technology A by pointing out (correctly, but in a misplaced manner) that Technology B can also backfire (in other words, a boolean logic argument). The devil is in the details. Hybridization cannot backfire nearly as much as genetic engineering. That is the salient point.

We cannot afford to excuse introducing new, barely tested technology under the excuse that we have been reckless in the past. Conventional breeding was a reckless endeavor. If we have played with a bomb in the past and made it alive, that does not create an excuse to play with a bomb yet again.

Regarding the safety testing performed on GMOs, I would put forth the following question: are there long term, multi-generational tests done on humans for any of the GMOs in circulation today to assess their safety? I would hope that the testing done by releasing them into the wild does not count as such, because this is merely testing after the fact.

You state that, while it is true that HGT is tested in nature's lab over millennia, crop improvement (in which we lump again various technologies) is nothing more than accelerated evolution. But traditional crop improvement, which we seek to tell apart from GE, is not HGT. From this perspective, the argument that we can justify HGT on grounds that man has been using other crop improvement techniques for ages appears flawed.

It is also important not to give GE undeserved hype. In the absence of GE, humanity can and will find other solutions to world hunger. It would be unfair to compare the world with GE with a world without GE and nothing else to replace it.

Where are the numbers that show that we need GMOs to feed the world populations?

Insofar as pesticide reduction is concerned, pesticide use should be reduced with or without GE. It’s through reckless games with chemicals like these pesticides that Man has polluted the whole biota with PCBs, DDTs, dioxins, and so forth. Everyone on Earth is currently polluted with persistent organic pollutants called PCBs. Not just every human, but every polar bear, every bird, every fish.

Ultimately, we are not asking that GE be banned. It can live in a lab and evolve there until we have a better handle on our testing. We simply question this hurry to put it in nature pervasively and irreversibly.

Don't miss the 2012 EFSA scientific assessment [1], in which they acknowledge that transgenesis can introduce novel risks into the food chain. Transgenesis is a form of genetic engineering in which we add foreign genes to a genome. Cisgenesis is a form of GE in which we take a gene indigenous to the genome, and that indeed is safer than cross-breeding through its targeting and because it doesn't risk perturbing the chemistry of the target phenotype. In short, transgenesis = all GE by which genes from otherwise incompatible species are brought into a genome, and that is a lot of GE.

Once again, the table is deceiving in that it does not discuss the most important detail: the fact that indigenous genes have learned to work within the organism, but foreign genes have not. HGT via GE introduces novel risks into the genome. That makes the table a bit of a red herring. ;)

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About Me

A scientist in a scientifically illiterate nation at a time when we need science the most.

Let me know if you need guidance with a science fair project, a scientific presentation, or would like me to visit with your school, church group, or organic coop. Believe it or not, these get togethers are always fun an we all learn something important.